Magnetic filter



June 9, 1964 M. BAERMANN 3,136,720

MAGNETIC FILTER Filed Nov. 8, 1960 2 Sheets-Sheet 1 FIG. 3

INVENTOR. MAX BAERMANN M. BAERMANN MAGNETIC FILTER June 9, 1964 2 Sheets-Sheet 2 Filed Nov. 8, 1960 FIG. 5

INVENTOR. MA X BAER MANN 4.- ATTORNEY United States Patent Ice 3,136,720 MAGNETIC FILTER Max Eaermann, Bensberg Wulshof, Bezirk Cologne (Rhine), Germany Filed Nov. 8, 1963, Ser. No. 67,987 Claimspriority, application Germany Dec. 12, 159 4 Glaims. (Cl. 210-222) This invention relates to a magnetic filter of the type employing permanent magnet means for separating. magneticallypermeable particles from a gaseous or liquid media. More particularly, the invention relates to a filter of the type described employing, as a permanent mag net, a flexible plastic material 'having dispersed therein particles of magnetic material adapted to be magnetized to produce a plurality of spaced north and south poles over its surfaces.

In .order to filter ferromagnetic particles and the like from a liquid or gas, it has heretofore been common to provide an assembly employing a plurality of rigid permanent magnets arranged to produce magnetic fields through which the fluid must pass whereby the ferromagnetic particles will be attracted to and cling to the magnets while the liquid or gaseous media passes through the filter. The difliculty with'such filters, however, is that a separate assembly of magnets is required for each filter size; and, depending upon the size of the filter, magnets of different shapes arerequired for different operating conditions. i

As a primary object, the present invention provides a new and'improved magnetic filter which overcomes the aforesaid disadvantages and others, said filter being formed from flexible plastic material having dispersed therein particles of permanent magnetic material.

More specifically, an object of the invention is to provide a magnetic filter in which strips of a flexible plastic material with magnetic particles dispersed therein may be rolled up into a spiral or arranged in layers to provide a filter of any size or shape.

In accordance with the invention, a permanent magnetic filter is provided formed from a strip of a flexible or resilient permanent magnet, such strip either being rolled into a spiral with successive turns being spaced one from the other, or cut into lengths which are arranged one upon the other in spaced relationship, in either case to provide spaced opposed surfaces. At least one of the opposed surfaces of the strip is magnetized with spaced north and south poles whereby a fluid containing magnetically permeable particles may pass through the spaces between layers of the strip while the particles cling to the magnetic poles. By virtue of the flexibility of the permanent magnetic strip, it may be used for all filter sizes so that the keeping in stock of different permanent magnetic and accessory parts is greatly simplified. Depending upon the size of the filter, a piece corresponding to the desired size is rolled into a spiral, or divided into single sections and arranged in layers.

Further in accordance with the invention, the magnetic strips of rubber-like plastic material are provided with raised portions or lugs extending across their widths such that when. the strip is cut into sections and arranged in layers or wound into a spiral, the raised portions will serve to space successive layers or turns through which a fluid may pass. Alternatively, layers or turns of the material may be corrugated to produce the same effect. If desired, however, smooth magnetic strips may be employed in combination with spacers or corrugated strips of non-magnetic material inserted between the layers or turns of the filter, as the case may be.

The above and other objects and features of the invention will become apparent from the following detailed hidiifififl Patented June 9, 1964 description taken in connection with the accompanying drawings which form a part of this specification and, in which:

FIGURE 1 is an illustration of a magnetic strip provided with raised portions or lugs extending across its width and magnetized to produce north and south poles on opposite edges of the strip;

FIGURE 2 is an illustration of a filter formed by winding a magnetic strip such as that shown in FIGURE 1 into a spiral;

FIGURE 3 is an illustration of a filter in which sections of the permanent magnetic strip shown in FIGURE 1 are arranged in spaced layers;

FIGURE 4 is an illustration of a filter in which sections of acorrugated permanent magnetic strip are arranged in layers to provide passageways through which a liquid or gaseous media may pass; and

FIGURE 5 illustrates one manner in which the permanent magnetic strip of FIGURE 1 may be magnetized to produce a highly efiicient filter.

Referring now to the drawings which are for the purpose of illustrating specific embodiments of the invention and not for the purpose of limiting the same, FIGURE 1 shows apermanent magnetic strip 10 comprised of a flexible or resilient plastic material having dispersed therein particles of permanent magnetic material. Preferably, the plastic binder comprises any of the well-known synthetic resins e.g. polyethylene which will harden into a flexible mass. Alternatively, the plastic binder may comprise natural rubber, neoprene, or the like. The magnetic particles within the binder may be iron-barium oxide or other suitable permanent magnetic material having a very high coercivity and a very low permeability. Although the foregoing should sufiice for purposes of the present application, a full and complete description of the composition and properties of this type of material may behad by reference to my copending application Serial No. 693,603, filed October 31, 1957, now Patent No. 2,959,832.

A characteristic of the magnetic strip formed from such magnetic particles dispersed throughout a plastic binder is that it may be magnetized with a plurality of north and south poles close spaced across one or more of its surfaces. Furthermore, the material may be magnetized with north and south poles extending parallel to its longitudinal surface or perpendicular thereto. In FIGURE 1, it will be noted that the material is magnetized along its length and parallel to its flat upper surface so that there is a north pole on one edge of the strip and a south pole on the other edge. Furthermore, the strip is magnetizedat spaced points across its width with reversed polarities. Extending across the width of the strip 10 are a plurality of spaced raised portions or lugs 12.

By rolling a magnetic strip such as that shown in FIG- URE 1 into a spiral, the magnetic filter shown in FIG- URE 2 will result. In order to hold the strip it] in assembled relationship, it is inserted into a housing 14 which comprises an outer cylindrical shell having rods or bars 16 extending across its opposite ends to retain the strip 10 therein. The purpose of lugs 12 become apparent in FIGURE 2. Thus, the lugs serve to separate successive turns of the spiral while leaving axially-extending passageways 18 through which a gaseous or liquid media may pass. The magnetic particles within the media will, of course, be attracted to the magnetic poles on strip 19; while the fluid passes through passageways 18. The surface of-the strip 10 should be as large as possible, and the fluid passing therethrough should move with the lowest possible speed to give the magnetically permeable particles within the fluid time to stick to the walls or surfaces of the strip ll). In order to clean the filter, the strip Ill will be removed from its housing and unrolled whereby the ferromagnetic particles or the like may be blown from the surface of the strip by compressed air or any other suitable means. After cleaning, the strip is again rolled into a spiral and inserted into its housing preparatory to another filtering operation.

In FIGURE 3 another embodiment of the invention is shown wherein the magnetic strip of FIGURE 1 is cut into equal lengths which are piled one above the other to produce a layered effect wherein the lugs 12 provide passageways through which a gaseous or liquid media may pass. The layered strips 10 are, like the embodiment of FIGURE 2, confined Within a housing 22 having bars or rods 24 at its opposite ends to retain the strips therein.

In the embodiment of FIGURE 4, magnetic strips 25 are corrugated and arranged within a housing 26 similar to that of FIGURE 3 and having bars 28 at its opposite ends. Preferably, the crests of the corrugations will abut each other as at 30 to provide passageways 32 of maximum cross-sectional area through Which a liquid or gaseous media may pass.

As was the case in FIGURE 2, the fiat or corrugated strips of FIGURES 3 and 4, respectively, may be taken out of their housings and cleaned with compressed air or any other suitable means after which they are ready for another filtering operation. The housings containing the magnetic strips in FIGURES 2, 3 and 4 may be formed from iron, aluminum or brass, or they may be formed from a plastic material such as nylon or Tefion. Although the bars at the opposite ends of the housings shown in FIGURES 24 are illustrated as an integral part thereof, it will be understood that in an actual installation the housing will be so constructed that a set of bars at one end of the housing may be removed to permit removal of the magnetic strips.

FIGURE 5 shows, in a greatly enlarged presentation, the path of the magnetic circuits between single plates 34, 3 6, 38 and 40 of a magnetic filter. In this case, the plates or strips 34-40 are magnetized perpendicularly to their flat surfaces With north and south poles alternating across the surfaces of the strips. Magnetic lines of flux 42 will come out of the north poles on plate 36 and go into the south poles on plate 34. The magnetic lines of flux 44, however, have the opposite direction and come out of the north poles on strip 34 and travel into the south poles on strip 36. The lines of fiux 46 and 48 come out of the north poles on plate 36 and go into the south poles of this same plate; while the lines 50 and 52 come out of the north poles of strip 34 and go into the south poles of the same plate. Thus, a complete closed path is provided for the magnetic lines of flux. The same situation is presented for the magnetic lines of flux 54 and 56. That is, the lines 54 will travel from the north pole at the center of strip 36 to the south pole on one side thereof; While the lines 56 will travel from this same north pole to the south pole on the other side thereof. With this construction, the resultant magnetic fields are. such that all ferromagnetic particles and the like Within a liquid or gaseous media passing through the filter will adhere to the strips 34-40 with great tenacity. Depending upon the use of the filter, the magnetizing can be accomplished, for example, so that no alternating magnetic poles are present in a lengthwise direction. In this case, the field lines 54 and 56 will, of course, not occur. In addition, the magnetization may be accomplished to suit requirements so that magnetic poles are present on only one side of the strips 34-40. In this case, the magnetic lines of flux extending between the strips also will not occur.

Although the invention has been shown in connection with certain specific embodiments, it will be readily apparent to those skilled in the art that various changes in form and arrangement of parts may be made to suit requirements without departing from the spirit and scope of the invention.

I claim:

1. An apparatus for filtering ferro-magnetic particles and the like from a fluid comprising superimposed, impervious layers of flexible material, said layer material comprising a flexible binder and particles of permanent magnetic material having a low permeability and a high coercivity in the order of the permeability and coercivity of iron-barium oxide dispersed within and bonded by said binder, each of said layers having a plurality of raised rib-like portions substantially integral with said layer and extending outwardly from at least one surface of said layer, a plurality of passageways defined between said rib-like portions for directing said fiuid along the surface of said layer between said rib-like portions and in substantially parallel flow paths, and said surface of said layer between said rib-like portions being substantially fiat and continuous and having at least one pair of north and south magnetic poles magnetized to produce flux lines that extend outwardly from said surface between said rib-like portions to form a high density flux field in said passageways with the flow of said fiuid in said passageways being substantially perpendicular to the axes of magnetization of said magnetic poles.

2. An apparatus as defined in claim 1 wherein said surface between said rib-like portions has a plurality of north and south magnetic poles alternating in polarity in the direction of flow of said fluid and extending transversely to the line of flow of said fluid.

3. An apparatus as defined in claim 1 wherein said superimposed layers are formed from a single sheet of said layer material and means for holding said sheet in a spiral configuration to form said apparatus.

4. An apparatus as defined in claim 1 wherein said superimposed layers are formed from separate sheets of said layer material and means for holding said sheets in stacked relationship to form said apparatus.

References Cited in the file of this patent UNITED STATES PATENTS 2,074,085 Frantz Mar. 16, 1937 2,816,665 Layte et a1. Dec. 17, 1957 2,893,561 Duzich July 7, 1959 2,999,275 Blume Sept. 12, 1961 3,024,392 Baermann Mar. 6, 1962 3,051,988 Baermann Sept. 4, 1962 

1. AN APPARATUS FOR FILTERING FERRO-MAGNETIC PARTICLES AND THE LIKE FROM A FLUID COMPRISING SUPERIMPOSED, IMPERVIOUS LAYERS OF FLEXIBLE MATERIAL, SAID LAYER MATERIAL COMPRISING A FLEXIBLE BINDER AND PARTICLES OF PRMANENT MAGNETIC MATERIAL HAVING A LOW PERMEABILITY AND A HIGH COERCIVITY IN THE ORDER OF THE PERMEABILITY AND COERCIVITY OF ION-BARIUM OXIDE DISPERSED WITHIN AND BONDED BY SAID BINDER, EACH OF SAID LAYERS HAVING A PLURALITY OF RAISED RIB-LIKE PORTIONS SUBSTANTIALLY INTEGRAL WITH SAID LAYER AND EXTENDING OUTWARDLY FROM AT LEAST ONE SURFACE OF SAID LAYER, A PLURALITY OF PASSAGEWAYS DEFINED BETWEEN SAID RIB-LIKE PORTIONS FOR DIRECTING SAID FLUID ALONG THE SURFACE OF SAID LAYER BETWEEN SAID RIB-LIKE PORTIONS AND IN SUBSTANTIALLY PARALLEL FLOW PATHS, AND SAID SURFACE OF SAID LAYER BETWEEN SAID RIB-LIKE PORTIONS BEING SUBSTANTIALLY FLAT AND CONTINUOUS AND HAVING AT LEAST ONE PAIR OF NORTH AND SOUTH MAGNETIC POLES MAGNETIZED TO PRODUCE FLUX LINES THAT EXTEND OUTWARDLY FROM SAID SURFACE BETWEEN SAID RIB-LIKE PORTIONS TO FORM A HIGH DENSITY FLUX FIELD IN SAID PASSAGEWAYS WITH THE FLOW OF SAID FLUID IN SAID PASSAGEWAYS BEING SUBSTANTIALLY PERPENDICULAR TO THE AXES OF MANETIZATION OF SAID MAGNETIC POLES. 